Intraoperative embolic stroke is one of the most dreadful complications of cardiac, aortic and vascular procedures, diagnosed in 1-22% of patients undergoing cardiovascular surgery. Even more frequently, in up to 70% of cases, patients undergoing heart, valve, coronary artery bypass and aortic surgery experience subclinical embolic events as recorded by transcranial Doppler and MRI. These embolic events lead to cognitive impairment and disability and have a significant impact on patients' recovery.
The main sources of cerebral emboli and stroke in this setting reside in the heart, heart valves, thoracic aorta, and great vessels when these structures are intervened thereon. Even simple cardiac catheterization with an endovascular catheter can induce microtrauma of the atherosclerotic thoracic aorta leading to formation of embolic particles with subsequent embolic brain injury ranging from latent ischemic foci to a massive or even fatal stroke.
Multiple devices are known that attempt to prevent embolization of the carotid arteries during endovascular and cardiac interventions. These anti-embolic devices, however, have not received wide acceptance in surgery of the heart, heart valves and thoracic aorta due to their complexity and invasive character with the risk of additional trauma to the inner vessel wall resulting in a high risk to benefit ratio. Known devices require insertion of additional hardware into the arterial system or aorta, a procedure that is known by itself to be associated with all classical risks of endovascular intervention, including aortic dissection, bleeding, thrombosis, and carotid cerebral embolization and stroke. One known intra-aortic filter device that is inserted into the ascending portion of the thoracic aorta via an aortic cannula to capture potential embolic material released from the heart and aortic wall during heart surgery was found to be quite difficult to implement and was reported to be associated with major trauma to aortic wall and acute aortic dissection.
Another such device for preventing emboli into the cerebral circulation includes a porous deflector/intra-aortic shield that captures or diverts potential emboli into the distal vasculature. A yet additional device has also been proposed for use during aortic valve surgery and is an intra-aortic filter catheter that captures emboli during this procedure. It has been established that intravascular filters are not able to capture emboli smaller than the pore size of the available devices (currently 60-140 μm) resulting in cerebral microembolization. Embolization may also occur due to poor apposition of the filter to the aortic or carotid arterial wall.
Furthermore, the placement of the filter by itself may produce cerebral emboli. For example, the mere passing of a guide wire into a carotid artery generates approximately 40,000 microemboli, with a significant percentage of small, less than 60 μm, particles that are not retained by standard filters. Therefore, in spite of multiple innovations in the field of anti-embolic devices, the problem of cerebral emboli and stroke during cardiovascular surgery is far from being resolved.
It is known to use balloon occlusion catheters for the prevention of embolic stroke. In this regard, the balloon occlusion catheter is placed inside of one of the carotid arteries when a procedure, for example carotid angioplasty and stenting, is conducted on the carotid artery in question. Although capable of preventing stroke when a single carotid artery is operated upon, this device cannot work to prevent stroke during procedures on the heart and aorta, endovascular or open, and cannot provide for bilateral occlusion. This device cannot simultaneously occlude both the left and right carotid arteries to prevent flow simultaneously through both of these arteries, and thus cannot prevent stroke should emboli flow into the non-blocked carotid artery.
Also, the design of known endovascular devices did not address the issue of specific orientation of balloons in carotid arteries. By failing to address this issue, the methods cause an increase in the amount of time and effort needed to make the placement and likewise cause a safety concern.
Further, known endovascular carotid occluding devices require a guide wire to be inserted into the carotid arterial system. This procedure by itself is known to induce carotid trauma and cause the formation of cerebral emboli and resultant stroke. Still additionally, prior endovascular carotid occluding devices are not capable of reducing arterial flow through both right and left vertebral arteries, either at the same time or individually. This deficiency may allow emboli to enter vertebral circulation and cause stroke.
Still further, known systems are not capable of interrupting the flow, if needed, to both vertebral arteries for the period of time when emboli can enter cerebral circulation. Known systems also risk trauma to the carotid artery wall and allow for subsequent cerebral emboli. As such, there remains room for variation and improvement within the art.
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention.